The present invention relates to the treatment of involuntary muscle dysfunctions. In particular, the present invention relates to the treatment of involuntary muscle dysfunction with relaxin hormone.
Involuntary muscle dysfunction plagues a large portion of the chronic pain and chronic fatigue patient population. Two prominent conditions involving involuntary muscle dysfunction include fibromyalgia and myofascial pain syndrome, amongst others.
Fibromyalgia is identified by the main symptoms of generalized chronic pain occurring mainly in the muscles and hyperalgesia, i.e. multiple tender points spread out over the body. The full range of symptoms include generalized pain, hyperalcesia, sleep disturbance, fatigue, muscle stiffness, hypersthesias, tension-type headaches, decreased muscle endurance and muscle weakness. Fibromyalgia has also been associated with irritable bowel syndrome, chronic fatigue syndrome, temporomandibular dysfunction syndrome, migraines, primary dysmenhorrea (painful menstruation) and others conditions including Raynaud's phenomenon. See Yunnus, Fibromyalgia Syndrome: Clinical Features and Spectrum, The Fibromyalgic Syndrome: Current Research and Future Directions in Epidemiology, Pathogenesis, and Treatment, 1994, pp. 5-21. See also Wolfe, When to Diagnose Fibromyalgia, Rheumatic Disease Clinics Of North America, Vol. 90, Number 2, May 1994. See Henriksson, Patogenesis of Fibromyalgia, Journal of Musculoskeletal Pain, 1993, Vol. 1, pp. 3-16.
Fibromyalgia is the second or third most common disorder seen in community practice. The economic effects of fibromyalgia are substantial. In one study, it was reported that only 60% of fibromyalgia patients were employed, 30% of patients changed jobs because of fibromyalgia, 10% of patients considered themselves disabled, and 6% received disability payments. See Rothschild et al, Retrospective Assessment of Fibromyalgia Therapeusis, Comprehensive Therapy 1994, Vol. 20, pp. 545-549.
Fibromyalgia also appears to be concentrated amongst the female patient population. It is estimated that about 80 to 90% of fibromyalgia patients are women. In addition, most patients are reported to fall in the 40 to 50 year age range. However, some studies have identified an archetypical patient as being a young women between the ages of 20 and 40. See Masi, A., Review of The Epidemiology and Criteria of Fibromyalgia and Myofascial Pain Syndromes: Concepts of Illness in Populations as Applied to Dysfunctional Syndromes, Journal of Musculoskeletal Pain, 1993, Vol. 1, pp. 113-116. See also Yunnus, supra, page 6.
While there is no current cure for fibromyalgia, it has been reported that some patients have responded to therapy with Halcion.RTM. and hypnosis. See Rothschild et al. However, these treatment modalities primarily address sleep disturbance and do not squarely address the cause of fibromyalgia or its full range of symptoms. Mvoreover, the use of Halcion.RTM. is not suitable for long-term treatment. While Halcion.RTM. induces sleep, Halcion also inhibits the patient's ability to achieve rapid eye movement (REM) sleep, which is necessary for therapeutic sleep.
Other conventional treatments of fibromyalgia include treating localized pain and muscle tension with intramuscular application of botulinum toxin as well as treatments including relaxation medication, exercise, and physical therapy. These latter treatment methods are aimed at relaxing and elongating the affected muscles.
However, none of these previous attempts at alleviating the symptoms of fibromyalgia and related involuntary muscle dysfunctions are effective. Moreover, these methods do not address the cause of fibromyalgia and other involuntary muscle dysfunctions.
In addition, many patients suffer from one or several of the symptoms (e.g., dysmenorrhea) associated with fibromyalgia without actually having fibromyalgia or the full range of symptoms. No single treatment is currently available for treating most or all of these symptoms.